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5311 |
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Wednesday, June 07, 2017, Hall 26 2:40 PM Wear Protection I |
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Sliding wear behavior of FeAl coatings at high temperature |
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Nuria Cinca* / University of Barcelona, Spain Slawomir Cygan/ The Institute of Advanced Manufacturing Technology. , POLAND Lucyna Jaworska / The Institute of Advanced Manufacturing Technology. , POLAND Sergi Dosta/ Thermal Spray Centre (CPT). Universitat de Barcelona. , SPAIN Irene G. Garcia Cano/ Thermal Spray Centre (CPT). Universitat de Barcelona. , SPAIN Cezary Senderowski/ Military University of Technology. , POLAND Josep M Guilemany/ Thermal Spray Centre (CPT). Universitat de Barcelona. , SPAIN |
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Iron aluminides have shown a significant improvement in tribological properties, including sliding and abrasive wear resistance, especially when reinforced with ceramic particles. In the last several years, some studies on the tribological properties of the Fe3Al based materials were mainly focused on dry-sliding, wet abrasive wear and corrosive environment tribology at room temperature but wear resistance materials at elevated temperatures are needed in a large number of industrial applications. In order to avoid the inconvenience that these intermetallics present when processing, they have been many times studied as coatings for their possible use at high temperatures, such as the use of FeAl as potential matrix instead of cobalt in WC-Co but there are not systematic studies reporting the sliding wear performance of iron aluminide coatings at intermediate and high temperatures. To produce the coatings evaluated in the present work, the Cold Gas Spray (CGS) and the High Velocity Oxygen Fuel (HVOF) techniques have been used for powders with the following nominal compositions: commercial Fe40at%Al powder and two experimental powders Fe46Al-6,55Si at% and FeAl+FexAly. It was observed that dense and pore-free coatings were obtained by CGS while the HVOF coatings contained Al-depleted regions, oxidation and significant porosity. The wear resistance and damage of the coatings against a Si3N4 ceramic ball was evaluated under 5N of load and at 400 and 800ºC by using a pin-on-disc tribotester. Results indicate that the lowest wear rates are found for the as-sprayed commercial powder with near the near stoichiometric Fe40at%Al composition at both testing temperatures although the differences in the hardness value are not much noticeable. In both conditions, some of the highest friction coefficients are presented, with an important contribution of an adhesion and delamination mechanisms. By contrast, the other compositions present brittle phases that result in a more extended damage of the wear tracks, with rapid removal of the coating and easily reaching the substrate. |